HU212852B - Method of producing absorption body, and absorption body - Google Patents

Abstract

The present invention relates to an absorption body (4) intended for an absorbent product, such as a sanitary towel or an incontinence guard, and comprising an absorbent material, preferably cellulose fluff, which increases in weight continuously from the edge margins (6) of the article in towards the centre part (5) thereof. According to the invention, the absorption body (4) is compressed to an essentially flat shape and exhibits a degree of compression which increases continuously from the edge margins (6) towards the centre part (5) of the body. The invention also relates to a method of producing an essentially flat absorption body (4), the density of which increases continuously from the edge margins (6) in towards the centre part (5) thereof.

Description

FIELD OF THE INVENTION The present invention relates to a method of forming an absorbent member having a density adjusted from the side edges to the middle of the absorbent member. Another object of the present invention is an absorbent member which is preferably used in sanitary napkins, diapers or incontinence pads, and comprises an absorbent material such as cellulose fluff.

One of the most serious problems in the production of various sanitary napkins and other diaper-like products is the ability to produce a diaper that does not leak during use. The most common site of leakage is at the side edges of the diaper. There are several reasons for such a leak, for example, when a diaper or pad is used in case of menstrual bleeding, and the fluid exiting the body so slowly enters the absorbent and fluid-absorbing portion that the peripheral portions that absorb the fluid become extremely they saturate quickly so that body fluid flows over the edges of the pad. Another and more general reason is that the diaper or liner itself is pressed against the other clothing of the wearer, and thus the surface which the liquid-receiving surface is significantly reduced. Equivalent to the latter problem is that in modern sanitary napkins and diapers, the part that is in contact with the body and the fluid emitting part is so narrow that it saturates very quickly. The purpose of the slim design is generally to provide the wearer with a comfortable feeling and to wear the insole in a sufficiently discreet manner.

Swedish Patent Application No. 349,476 discloses a sanitary napkin or diaper or sanitary napkin having an absorbent body comprising a fibrous absorbent material, wherein the amount of fibrous absorbent material per unit volume applied in the longitudinal and transverse directions is variable.

Most of the absorbent material is disposed on the portion of the diaper or liner that is first in contact with the liquid, and the amount of absorbent material in the liner, which is per unit volume within the liner, gradually decreases away from this range. The thickness of this known absorbent member is practically the same across its entire cross-section, but due to the material density due to the pressure applied to it during use, the middle portion of the insert can expand more. As a result, the pad or diaper will be ellipsoidal, which is advantageous in that it increases the wearer's comfort.

However, the disadvantage of this known solution is that, since the material is easily compressed or otherwise deformed during extremely soft and deformable use, it is predominantly transverse and thus increases the risk of leakage. A further major disadvantage of these sanitary napkins or pads is that they swell in use and thus cannot be worn discreetly enough. We have found that people who use sanitary napkins or absorbent pads find it very important that one of the most important requirements for these pads is that they can be worn very discreetly and that they can be worn practically with everyday clothing notice. It is important, therefore, for a very discreet sanitary napkin to be very thin. However, it is also a requirement that it be comfortable to wear with its thinness, which is not guaranteed with a thick swollen or thick diaper or pad.

U.S. Pat. No. 3,545,441; U.S. Pat. No. 4,123,195 discloses an absorbent core which is formed to be substantially the same thickness before being used and is not exposed to external force. In use, when the absorbent core is subjected to pressure, its shape will be slightly elongated due to the applied pressure, so that its cross-section is already variable in size. The essence of this design of the absorbent core is that the density is transversely shaped so that where the greatest amount of liquid discharge is expected, that is the center of the absorbent core, there is a greater number of filaments per unit volume, i.e., greater density than where less liquid emptying is expected, ie at the edges. The disadvantage of this solution is that due to the pressure it takes on a slightly curved shape, its surface is concave, and when suddenly large volumes of fluid are discharged, it cannot be quickly absorbed and wetted under the side edges or, if appropriate, leaked onto the skin.

It is an object of the present invention to provide an absorbent element which overcomes the shortcomings of the above solutions, which can be used as sanitary napkins or as incontinence pads, and which clearly overcome the problems that have arisen.

The present invention thus provides a method of producing an absorbent member having a density adjusted from the side edges to an increasing portion of the center of the absorbent member, which process preferably comprises forming a cellulose-containing fluff with a transverse section preferably of triangular shape; exposing the element to be molded along its entire surface so that the side edges at least partially regain their original thickness after the end of the compression effect and the compressed state is maintained in the central region even after the end of the compression effect.

Another preferred embodiment of the invention is that the pressure is exerted by passing the element to be machined through two roller rollers which are spaced at a predetermined distance from each other and exerting a greater pressure on the central portion of the absorbent member.

It is also advantageous for the process according to the invention to provide a greater compression effect on the central portion by means of protruding elements disposed on the rollers. then the element to be machined is a cell mixed with air2

It is made from a lotion flake and formed into a web with a casting drum.

The present invention further relates to an absorbent member which is preferably used in sanitary napkins, diapers or incontinence pads, and is comprised of an absorbent material, such as cellulose fluff, and is formed according to the invention to be thinnest at the central portion of the absorbent body. towards gradually increasing.

Preferably, the absorbent member according to the invention has a material density at the lateral edges which is lower than the central portion or provided with a longitudinal recess and has the highest stiffness and highest density within this range.

The absorbent member according to the invention has several advantages. As the center portion is more compressed, the absorbent member provides very good under-stability and is effectively resistant to forces that want to compress or deform this shape. Despite its relatively high rigidity and resistance to compression and other deformation, the edges of the element are sufficiently soft and capable of deformation. The product according to the invention is extremely comfortable to wear and can be used in combination with various of the above-mentioned solutions, furthermore, it has a very good absorption capacity and is very discreet to wear.

The high absorbency of the article according to the invention is due to the fact that the absorbent body contained therein contains relatively large amounts of absorbent material, on the one hand, and the utilization of this absorbent material, on the other hand, is extremely good because of its excellent dispersing ability. Thus, the fluid contained therein is extremely fast in the fine capillaries, the absorbed liquid being first dispersed along the longitudinal direction of the absorbent body, since the material density is selected to be higher in this direction, which also means that the distance between fibers or particles is also small. On the other hand, when high density regions become saturated with liquids, the liquid will propagate transversely.

Since the absorbent property itself is configured so that its density gradually increases from the edges to the center of the element, the size of the fluid transfer channels between the absorption walls will decrease accordingly. This means that the liquid deposited at the edge of the absorbent body will move toward the center of the absorbent body, under the influence of suction, since the capillaries are characterized by the flow of fluid from the coarser or larger diameter towards the finer. Thus, the edge of the absorbent member will always remain dry, provided that its absorption capacity in the central portion is not exhausted. Thus, the likelihood of leakage on the side portions of the absorbent member of the invention is minimal, even if, for some external reason, the pad or diaper slides laterally during use.

The extremely low thickness of the element according to the invention allows it to be worn discreetly, and it is also advantageous that it can be manufactured in much smaller packing techniques.

Since the absorbent member is narrower in its central region, the body itself is formed with a trough-like liquid receiving portion. The outer part having a greater thickness essentially prevents the liquid from leaking there, and thus prevents the liquid from reaching the edges before sucking. This is particularly advantageous for incontinence diapers which have to absorb relatively large amounts of fluid in a relatively short period of time.

The process according to the invention and the absorbent element according to the invention will now be described in more detail by means of exemplary embodiments in the accompanying drawings. The

1, an absorbent member of the diaper according to the invention is exemplified,

Figure 2 is a sectional view taken along line II-II in Figure 1, a

Figure 3 is a top view of a finished absorbent member, a

Figure 4 is a sectional view taken along line IV-IV of Figure 3, while

Fig. 5 is a schematic view of Figs. Scheme for the manufacture of a sanitary napkin or a napkin according to claim 1.

Figures 1 and 2 show the element 1 to be formed which is formed of a cellulosic flake having a substantially triangular cross-section. In this embodiment, the absorbent material forming the element 1 to be formed is arranged to be concentrated near its longitudinal axis. The absorbent material from which the hollow member is formed is formed such that the density of the material decreases as it moves away from the center towards the side edges 6. Now, by compressing this element to be formed, a substantially flat absorbent element is obtained. If the compression force is high enough, the lateral edges 6 of the absorbent member will bounce back easily when this compression force is removed while the thickness produced by the pressure will remain in the central portion 5.

In this way, of course, the absorbent member that we have created will have the thinnest but highest density portion along its centerline in the center portion where the absorption is relatively high and the material at the lateral edges will be thicker but its density is lower. The transition takes place gradually with the compressed center portion 5 towards the larger volume side edges 6 with no apparent boundary.

In the embodiment shown in Figures 3 and 4, a liquid-permeable layer 2 can be observed which can be formed, for example, from fibers or, for example, from a perforated film. the 3

The liquid impermeable layer may also be a plastic film or a hydrophobic fiber material. The fluid-permeable layer 2 and the fluid-impermeable layers are joined to one another along the flanges and the absorbent body 4 will be located therebetween.

As shown in FIG. 4, the pad or diaper thus formed has a minimum thickness in the middle portion 5 and a much greater thickness and volume than the side edges 6. As previously indicated, the turtle-like design allows the fluid receiving surface to be formed in the central portion 5, while the lateral edges 6 act as fluid barriers and lie on the wearer's body.

For example, sanitary napkins and pads of the present invention may be made by the process of Figure 5. Fig. 5 shows that the element 1 to be formed is arranged in a mesh-like pattern 9 which is applied to a rotating drum 8. From this rotating drum 8, each element 1 to be formed is moved to a moving conveyor belt 10, such that the element 1 is inserted between the fluid impermeable web 11 and the fluid permeable web 12, and is then routed together between the rotating rollers 13 and 14, a certain distance between them remains. The liquid impermeable fabric 11 and the liquid impermeable fabric 12 are guided from two spools 15 and 16, and at least one of them is covered with molten adhesive, which can be applied, for example, from a spray unit 17. The liquid impermeable fabric 11 is joined to the liquid permeable fabric 12 along its edges along the edges of the workpiece to be molded, and in the exemplary embodiment is simultaneously glued together with the adhesive applied to the liquid impermeable layer 11. The degree to which the element to be machined 1 is compressed or the degree to which it is applied will depend on a number of parameters, such as the distance between the rotating rollers 13 and 14, the moisture content of the cellulose flake used, and we use fluff of the nature. These factors also interact with each other, so it is very difficult to determine in advance how these press rollers 13 and 14 can be optimally adjusted. Preliminary experiments should be carried out. For example, the moisture content of the flakes is very significant in terms of the pressure result. Since the moisture content of a particular flake varies with the season, time, and other parameters that may not be known, it is advisable to first experimentally establish the roller distance or compression ratio for each new flake.

The sanitary napkins or diapers thus formed are then placed on a suitable cutting tool, such as a cutting roll, and then packaged. Separation or packaging is not shown in the figure, but can be achieved in a manner known per se.

The basic idea of the invention, however, can be realized by means of the embodiments according to the invention, which are clearly illustrated but which are not shown in the figures, but which reflect the spirit of the invention. For example, the rollers 13 and 14 may be provided with prohontories, which ensure that a very high pressure is applied to the central portion. This ensures that the sanitary napkin remains properly compressed in the central area, even after the compression has ceased.

Claims (8)

PATENT CLAIMS A method for producing an absorbent member having an increasing density adjusted from the side edges to the central portion of the absorbent member, characterized in that a cellulose-containing fluff is formed into a moldable element, preferably having a transverse section, which is printed across its entire surface. so that, after cessation of compression, the lateral edges are at least partially restored to their original thickness, while in the central region the compressed state is maintained even after cessation of compression. Method according to claim 1, characterized in that the pressure is applied by passing the element to be formed between two pressure rollers which are at a predetermined distance from each other. 3. A method according to claim 1 or 2, wherein the central portion of the absorbent member is exerted more heavily than the other portion. Method according to Claim 2 or 3, characterized in that the greater compression effect on the central part is achieved by protruding elements on the rollers. 5. A method according to any one of claims 1 to 4, characterized in that the element to be formed is made of air-mixed cellulose flakes and is formed on a rotary drum with a mesh mold. An absorbent member, preferably for sanitary napkins, diapers, or incontinence pads, comprising an absorbent material, such as cellulose fluff, characterized in that it is thinnest at the center (5) of the absorbent body (4) and has a thickness toward the side edge. (6) gradually increasing. An absorbent member according to claim 6, characterized in that the side edges (6) have a material density lower than the central portion (5). An absorbent member according to claim 6 or 7, characterized in that it is provided with a longitudinal recess and has a maximum stiffness and maximum density in this range.